Apparent Motion

1. Apparent Motion

2. What is apparent motion? • Important to understand what we see and what is actually happening. • Apparent motion is what we see from Earth • Actual motion is what is really happening • EX: The sun appears to move around us, but really we are rotating on our axis causing the sun to rise and set.

3. Celestial Spheres

4. Vocabulary • Zenith- Point directly above the observers head and is 90 degrees from each horizon • North Celestial Pole- Equals the observer’s latitude • Celestial Equator- 90 degrees minus the observers latitude ( for Lacey it would be 90-47= 43 degrees) and it is the sun’s path during both the vernal and autumnal equinox. • Winter solstice-Celestial Equator – 23.5 degrees (path the sun takes on the shortest day of the year) • Summer solstice- Celestial Equator + 23.5 degrees(path the sun takes on the longest day of the year)

5. Why do we see this? • Celestial Sphere 3D • Sun Motion 3D • Stars- North Sky We are at 47 degrees North which means that the North Celestial Pole points to our north star Polaris. This also means that the NCP is at 47degrees above the horizon. North Star 47 ◦ North

6. Circumpolar • Circumpolar stars are those which rotate a full circle around the North Celestial Poles • At any latitude, circumpolar stars would be those that are within that many degrees of the horizon. • EX Seattle is 47degrees north so any stars that are within 47 degrees of the north star will rotate around the star in a full circle. • What would the stars look like at the north pole? What about the equator? TIME LAPSE Video of Circumpolar Stars

7. Stars in the Southern Sky • Stars in the southern sky will follow the same pattern as the sun and the moon. • The stars will rise in the East and set in the west. Time Lapse of Stars in South sky 8:00pm 3:00am E W S